eit.c

Dvbstreamer 用在解析MPTS的部分内容

                              void * p_private_decoder,
                              dvbpsi_psi_section_t * p_section)
{
  dvbpsi_eit_decoder_t* p_eit_decoder
                        = (dvbpsi_eit_decoder_t*)p_private_decoder;
  int b_append = 1;
  int b_reinit = 0;
  unsigned int i;

  DVBPSI_DEBUG_ARG("EIT decoder",
                   "Table version %2d, " "i_table_id %2d, " "i_extension %5d, "
                   "section %3d up to %3d, " "current %1d",
                   p_section->i_version, p_section->i_table_id,
                   p_section->i_extension,
                   p_section->i_number, p_section->i_last_number,
                   p_section->b_current_next);

  if(!p_section->b_syntax_indicator)
  {
    /* Invalid section_syntax_indicator */
    DVBPSI_ERROR("EIT decoder",
                 "invalid section (section_syntax_indicator == 0)");
    b_append = 0;
  }

  /* Now if b_append is true then we have a valid EIT section */
  if(b_append)
  {
    /* TS discontinuity check */
    if(p_psi_decoder->b_discontinuity)
    {
      b_reinit = 1;
      p_psi_decoder->b_discontinuity = 0;
    }
    else
    {
      /* Perform a few sanity checks */
      if(p_eit_decoder->p_building_eit)
      {
        if(p_eit_decoder->p_building_eit->i_service_id != p_section->i_extension)
        {
          /* service_id */
          DVBPSI_ERROR("EIT decoder",
                       "'service_id' differs"
                       " whereas no TS discontinuity has occurred");
          b_reinit = 1;
        }
        else if(p_eit_decoder->p_building_eit->i_version
                                                != p_section->i_version)
        {
          /* version_number */
          DVBPSI_ERROR("EIT decoder",
                       "'version_number' differs"
                       " whereas no discontinuity has occurred");
          b_reinit = 1;
        }
        else if(p_eit_decoder->i_last_section_number !=
                                                p_section->i_last_number)
        {
          /* last_section_number */
          DVBPSI_ERROR("EIT decoder",
                       "'last_section_number' differs"
                       " whereas no discontinuity has occured");
          b_reinit = 1;
        }
      }
      else
      {
        if(    (p_eit_decoder->b_current_valid)
            && (p_eit_decoder->current_eit.i_version == p_section->i_version))
        {
          /* Signal a new EIT if the previous one wasn't active */
          if(    (!p_eit_decoder->current_eit.b_current_next)
              && (p_section->b_current_next))
          {
            dvbpsi_eit_t* p_eit = (dvbpsi_eit_t*)ObjectCreateType(dvbpsi_eit_t);

            p_eit_decoder->current_eit.b_current_next = 1;
            *p_eit = p_eit_decoder->current_eit;
            p_eit_decoder->pf_callback(p_eit_decoder->p_cb_data, p_eit);
          }

          /* Don't decode since this version is already decoded */
          b_append = 0;
        }
      }
    }
  }

  /* Reinit the decoder if wanted */
  if(b_reinit)
  {
    /* Force redecoding */
    p_eit_decoder->b_current_valid = 0;
    /* Free structures */
    if(p_eit_decoder->p_building_eit)
    {
      ObjectRefDec(p_eit_decoder->p_building_eit);
      p_eit_decoder->p_building_eit = NULL;
    }
    /* Clear the section array */
    for(i = 0; i <= 255; i++)
    {
      if(p_eit_decoder->ap_sections[i] != NULL)
      {
        dvbpsi_ReleasePSISections(p_psi_decoder, p_eit_decoder->ap_sections[i]);
        p_eit_decoder->ap_sections[i] = NULL;
      }
    }
  }

  /* Append the section to the list if wanted */
  if(b_append)
  {
    int b_complete;

    /* Initialize the structures if it's the first section received */
    if(!p_eit_decoder->p_building_eit)
    {
      dvbpsi_NewEIT(p_eit_decoder->p_building_eit,
                     p_section->i_extension,
                     p_section->i_version,
                     p_section->b_current_next,
                     ((uint16_t)(p_section->p_payload_start[0]) << 8)
                     | p_section->p_payload_start[1],
                     ((uint16_t)(p_section->p_payload_start[2]) << 8)
                     | p_section->p_payload_start[3],
                     p_section->p_payload_start[4],
                     p_section->p_payload_start[5]);
      p_eit_decoder->i_last_section_number = p_section->i_last_number;
      p_eit_decoder->i_first_received_section_number = p_section->i_number;
    }

    /* Fill the section array */
    if(p_eit_decoder->ap_sections[p_section->i_number] != NULL)
    {
      DVBPSI_DEBUG_ARG("EIT decoder", "overwrite section number %d",
                       p_section->i_number);
      dvbpsi_ReleasePSISections(p_psi_decoder, p_eit_decoder->ap_sections[p_section->i_number]);
    }
    p_eit_decoder->ap_sections[p_section->i_number] = p_section;

    /* Check if we have all the sections */
    b_complete = 0;

    /* As there may be gaps in the section_number fields (see below), we
     * have to wait until we have received a section_number twice or
     * until we have a received a section_number which is
     * first_received_section_number - 1;
     * if the first_received_section_number is 0, it's enough to wait
     * until the last_section_number has been received;
     * this is the only way to be sure that a complete table has been
     * sent! */
    if((p_eit_decoder->i_first_received_section_number > 0 &&
        (p_section->i_number ==
           p_eit_decoder->i_first_received_section_number ||
         p_section->i_number ==
           p_eit_decoder->i_first_received_section_number - 1)) ||
       (p_eit_decoder->i_first_received_section_number == 0 &&
        p_section->i_number == p_eit_decoder->i_last_section_number))
    {
      for(i = 0; i <= p_eit_decoder->i_last_section_number; i++)
      {
        if(!p_eit_decoder->ap_sections[i])
          break;

        if(i == p_eit_decoder->i_last_section_number)
        {
          b_complete = 1;
          break;
        }

        /* ETSI EN 300 468 V1.5.1 section 5.2.4 says that the EIT
         * sections may be structured into a number of segments and
         * that there may be a gap in the section_number between
         * two segments (but not within a single segment); thus at
         * the end of a segment (indicated by
         * section_number == segment_last_section_number)
         * we have to search for the beginning of the next segment) */
        if(i == p_eit_decoder->ap_sections[i]->p_payload_start[4])
        {
          while(!p_eit_decoder->ap_sections[i + 1] &&
                (i + 1 < p_eit_decoder->i_last_section_number))
          {
            i++;
          }
        }
      }
    }

    if(b_complete)
    {
      /* Save the current information */
      p_eit_decoder->current_eit = *p_eit_decoder->p_building_eit;
      p_eit_decoder->b_current_valid = 1;
      /* Chain the sections */
      if(p_eit_decoder->i_last_section_number)
      {
        dvbpsi_psi_section_t * p_prev_section;

        p_prev_section = p_eit_decoder->ap_sections[0];
        for(i = 1; i <= p_eit_decoder->i_last_section_number; i++)
        {
          if(p_eit_decoder->ap_sections[i] != NULL)
          {
            p_prev_section->p_next = p_eit_decoder->ap_sections[i];
            p_prev_section = p_eit_decoder->ap_sections[i];
          }
        }
      }
      /* Decode the sections */
      dvbpsi_DecodeEITSections(p_eit_decoder->p_building_eit,
                               p_eit_decoder->ap_sections[0]);
      /* Delete the sections */
      dvbpsi_ReleasePSISections(p_psi_decoder, p_eit_decoder->ap_sections[0]);
      /* signal the new EIT */
      p_eit_decoder->pf_callback(p_eit_decoder->p_cb_data,
                                 p_eit_decoder->p_building_eit);
      /* Reinitialize the structures */
      p_eit_decoder->p_building_eit = NULL;
      for(i = 0; i <= p_eit_decoder->i_last_section_number; i++)
        p_eit_decoder->ap_sections[i] = NULL;
    }
  }
  else
  {
    dvbpsi_ReleasePSISections(p_psi_decoder, p_section);
  }
}


/*****************************************************************************
 * dvbpsi_DecodeEITSections
 *****************************************************************************
 * EIT decoder.
 *****************************************************************************/
void dvbpsi_DecodeEITSections(dvbpsi_eit_t* p_eit,
                              dvbpsi_psi_section_t* p_section)
{
  uint8_t* p_byte, * p_end;

  while(p_section)
  {
    for(p_byte = p_section->p_payload_start + 6;
        p_byte < p_section->p_payload_end - 12;)
    {
      uint16_t i_event_id = ((uint16_t)(p_byte[0]) << 8) | p_byte[1];
      dvbpsi_date_time_t t_start_time;
      dvbpsi_eit_event_duration_t t_duration;
      uint8_t i_running_status = (uint8_t)(p_byte[10]) >> 5;
      int b_free_ca = (int)(p_byte[10] & 0x10) >> 4;
      uint16_t i_length = ((uint16_t)(p_byte[10] & 0xf) << 8) | p_byte[11];

      dvbpsi_DecodeMJDUTC(&p_byte[2], &t_start_time);

      t_duration.i_hours   = (((unsigned int)(p_byte[7] >> 4) & 0xf) * 10) + ((unsigned int)(p_byte[7] & 0xf));
      t_duration.i_minutes = (((unsigned int)(p_byte[8] >> 4) & 0xf) * 10) + ((unsigned int)(p_byte[8] & 0xf));
      t_duration.i_seconds = (((unsigned int)(p_byte[9] >> 4) & 0xf) * 10) + ((unsigned int)(p_byte[9] & 0xf));      

      dvbpsi_eit_event_t* p_event = dvbpsi_EITAddEvent(p_eit,
          i_event_id, &t_start_time, &t_duration,
          i_running_status, b_free_ca);
      /* Event descriptors */
      p_byte += 12;
      p_end = p_byte + i_length;
      while(p_byte + 2 <= p_end)
      {
        uint8_t i_tag = p_byte[0];
        uint8_t i_length = p_byte[1];
        if(i_length + 2 <= p_end - p_byte)
          dvbpsi_EITEventAddDescriptor(p_event, i_tag, i_length, p_byte + 2);
        p_byte += 2 + i_length;
      }
    }

    p_section = p_section->p_next;
  }
}